Update to Swift 4.2

Package.resolved

@@ -2,21 +2,21 @@
   "object": {
     "pins": [
       {
-        "package": "CSSH",
-        "repositoryURL": "https://github.com/jakeheis/CSSH",
+        "package": "Socket",
+        "repositoryURL": "https://github.com/IBM-Swift/BlueSocket",
         "state": {
           "branch": null,
-          "revision": "579a20508ab598f78713a60fed95706efd06bbcb",
-          "version": "1.0.3"
+          "revision": "26c8f4e4e3000421a0c97aaf0c7b5e9aa5475222",
+          "version": "0.12.94"
         }
       },
       {
-        "package": "Socket",
-        "repositoryURL": "https://github.com/IBM-Swift/BlueSocket",
+        "package": "CSSH",
+        "repositoryURL": "https://github.com/jakeheis/CSSH",
         "state": {
           "branch": null,
-          "revision": "d42af4542b6d5a0114fc6a4aae479c454b52b64a",
-          "version": "0.12.68"
+          "revision": "579a20508ab598f78713a60fed95706efd06bbcb",
+          "version": "1.0.3"
         }
       }
     ]

Sources/Bindings/Channel.swift

@@ -54,7 +54,7 @@ public class Channel {
         var data = Data(repeating: 0, count: Channel.bufferSize)
         
         let rc: Int = data.withUnsafeMutableBytes { (buffer: UnsafeMutablePointer<Int8>) in
-            return libssh2_channel_read_ex(cChannel, 0, buffer, data.count)
+            return libssh2_channel_read_ex(cChannel, 0, buffer, Channel.bufferSize)
         }
         
         try LibSSH2Error.checkOnRead(code: Int32(rc), session: cSession)

Sources/Bindings/Error.swift

@@ -43,7 +43,7 @@ public struct LibSSH2Error: Swift.Error {
         var messagePointer: UnsafeMutablePointer<Int8>? = nil
         var length: Int32 = 0
         libssh2_session_last_error(session, &messagePointer, &length, 0)
-        let message = messagePointer == nil ?  "Error" : String(cString: messagePointer!)
+        let message = messagePointer.flatMap({ String.init(cString: $0) }) ?? "Error"
         self.init(code: code, message: message)
     }